Generation of electrical power is a process in which one form of energy is converted into electricity, and a great plurality of processes is known and used today for performing the same. Some of these processes involve turning one form of energy into mechanical energy allowing the movement/rotation of a mechanical element within a magnetic field for the generation of electricity.
Some of these processes are as follows:                burning coal in order to turn water into steam and allowing the steam to expand within and revolve a turbine, the turbine being the mechanical element;        using solar energy in order to turn water into steam and implementing the same;        using the power of a waterfall for driving a turbine;        burning gas within a combustion chamber to drive a piston (for example in an internal combustion engine);        
In addition, there also exist processes for the generation of electricity which rely on the compression/expansion of a medium, entailing reciprocation/movement of a mechanical element. In some of these processes, compression/expansion of the medium is performed by heating/cooling thereof.
Such systems are disclosed, for example, in the following publications: GB1536437, WO2009064378A2, US2008236166A1, US2005198960A1, US2006059912A1 etc.